If the former TD and senator had been an ordinary Joe Bloggs who fraudulently claimed €4,207.45 from his employer and paid it all back (albeit when it seemed that he was about to be rumbled), does anybody think Callely would be spending the next few months in jail?

It's actually the inverse of the traditional claim that there is one law for politicians and one law for everybody else.

Judge Mary Ellen Ring was quite clear yesterday that Callely's role as a politician was a significant factor in her ruling.

He not only broke the law, she said, but he had engaged in a "significant breach of trust" because he was a public representative.

A custodial sentence was needed in the public interest.

And it was more the fact of that sentence, rather than its length, that was most important.

Judge Ring is by all accounts an excellent judge. Tough, but balanced and fair is the assessment of those who have watched her in action.

And, of course, she has a point when she argues that, while public representatives cannot be expected to be superhuman, they must be held to a higher standard. It's arguably the same for anybody in a position of trust – teachers, bankers, doctors, solicitors etc. Everybody, including politicians, is equal before the law.

But it's inevitable that a tougher line will be taken with certain categories of people who break the law, not least "pour encourager les autres", as Voltaire famously put it.

But there's still a nagging feeling that Callely's sentence, for what is a relatively minor transgression, is overly harsh.

Prison, as his defence counsel Michael O'Higgins legitimately pointed out yesterday, should be a last resort.

The former junior minister isn't a character who will naturally attract a lot of sympathy. His nickname 'Ivor the Driver' is indicative of not just the undoubted energy he brought to politics, but also an overweening ego and ambition. His thirst for publicity rubbed his colleagues up the wrong way.

Callely has also been involved in far too much low-level controversy over the years, including the revelation a few years back that a construction company arranged for his home to be painted for free in the early 1990s.

Then there was the very high rate of turnover in his ministerial office and the disclosure about him claiming travelling expenses from his holiday home in west Cork to Leinster House, which he explained by calling it his 'principal residence'.

Add in the bogus paperwork for his mobile phone expenses, and his initial attempts to put the blame on a deceased former business partner.

Callely is no paragon of virtue, to put it bluntly but is still small potatoes when measured alongside his one-time constituency colleague, the disgraced former Taoiseach Charlie Haughey.

The Moriarty Tribunal put a value of €45m in today's terms on Haughey's corruption – more than 10,000 times the amount Callely has been convicted of defrauding.

But despite being accused by Moriarty of devaluing the quality of a modern democracy, Haughey never faced trial for his actions in this regard.

Judge Mary Ellen Ring's summing up yesterday was thoughtful and considered. Few will find fault with it. There's no question that what Callely did was completely wrong (although if every worker who diddled their expenses was prosecuted and imprisoned the prison system wouldn't be able to cope).

And, coming from a public representative, it was unquestionably a "significant breach of trust".

But that doesn't take away from the reality that amidst all the featherbedding and corruption that went on in Irish society over the past 30 years, Callely is one of the few to feel the full force of the law. And for a crime valued at €4,207.45.

He will be held in prison for the next few months at considerable expense – it will cost the taxpayer a massive multiple of the amount he was convicted of defrauding.

To what end? Public opinion – including the voices who claimed no politician ever goes to prison – may be sated for a time. A marker has certainly been laid down. But does the punishment fit the crime?

Shane Coleman is the presenter of 'The Sunday Show' on Newstalk 106-108FM